This invention relates to a detector system for knitting machines and more particularly to sensor employed in manufacturing operations to detect defects in knitting fabric.
There is a variety of devices available for use on circular knitting machines to reduce the occurrence of fabric defects such as yarn breaks, holes in the fabric, runs in the fabric, etc.
Normally the instruments for assuring better quality knitted fabric consist of devices which sense yarn breakage in its passage from a yarn supply to the knitting elements of the circular knitting machine, and devices for sensing fabric condition between the knitting elements and the fabric take-down assembly.
One of the more commonly used detectors is an electrical device for stopping operation of the knitting machine when a yarn breaks or runs out.
Devices for detecting holes and runs in fabric also are commonly used for automatically stopping operation of the machine. These may be in the form of mechanical fingers or electronic devices for optical scanning of the fabric to locate defects. However, as in the case of rundown detectors, the prior art forms have certain disadvantages. For example, such devices do not have the ability to detect good fabric from bad fabric. Sometimes in oiling the knitting machines, oil may cause streaks on the fabric, thus giving false signals of a run in the fabric. Once the machine has been restarted, the system of the present invention prevents the rundown detector from stopping the machine again until a prescribed amount of faultless fabric has been sensed by the rundown detector.
A primary object of the invention is the provision of a new and improved fault detection system for knitting machines.
Another object of the invention is to provide a novel rundown detector which substantially eliminates the stopping of the machine due to false signals and deactivates the machine only in the event of an actual rundown defect in the fabric.
It is another object of the invention to provide a rundown detector which incorporates a fiber optic means and a floating head for sensing the condition of the fabric.
A further object of the invention is to provide a kntting machine incorporating a system for deactivating the machine upon detection of a rundown, a yarn break, or occurrence of an opening in the fabric.
Still another object of the invention is a fault detection system which is reliable in operation and which may be economically applied to existing knitting machines.
Other objects and advantages of the invention will become apparent when considered in view of the following detailed description.